Human refractive error typically diminishes over the first postnatal year, while the neural system is undergoing significant development. Progression of both processes is critically dependent on visual experience and the quality of the retinal image. Retinal image quality, however, is likely to be compromised in young infants due to accommodative immaturities. This proposal will examine the accommodative abilities of infants and qualify the real-time impact of immaturities on retinal image quality during the first postnatal year. These data will enable a refined understanding of the interdependence of accommodation, neural resolution and emmetropization in human development, as well as determine the impact of each on manifest visual function.